MOI isn't very intuitive for holes when you first start using it, especially if you've moved from a CAD environment

If you want to drill a partial depth hole then you can use extrude/bothsides to your correct depth and boolean it out

ado1, I trained using Solidworks, and tbd, MoI3D comes pretty close in terms of workflow. Sure, there are differences of course, as Solidworks, at least the 2001 version of SW, is a full-on industrial/mechanical CAD experience. But the overall feel of MoI3D is more Solidworks than say, Cheetah3D. I love how MoI3D is very precise when using measurements. Few other 'modelling' CAD's offer that on a budget. It's brilliant that Michael Gibson is still after all these years supporting MoI3D, and because of I'll probably buy a copy as soon as I get paid.

But back to the countersinks, thanks to all about the chamfer. I initially tried that but it didn't work. But now I understand why.